Ars reviews the mid-2011 MacBook Air

Size and weight
Good screen
Excellent backlit keyboard
Long maximum battery life
CPU performance on par with last year's MacBook Pros
Thunderbolt port
Network recovery

No Kensington slot
Network options are a bottleneck for local file transfers
Hard to get the best battery performance in real-world use
Software support for higher resolution display incomplete
iLife software tied to your account, can't be resold with the machine
Network recovery